The word “monism” goes back to Christian Wolff (Psychologia Rationalis, para. 32), but an equivalent idea is found as early as Aristotle (Metaphysics, 986b 21). The reality it denotes is a doctrine which seeks to explain reality (as a whole or in part) by a single principle intrinsic to it, despite its unmistakable multiplicity and variety. This can be done by reducing all kinds of being to one (monism of kind; relative monism). Or it can be done by denying the multiplicity of independent beings (substances) by point…